What's the difference...

[cfullgraf]

As a side point, the grip frames on the K and L frames are the same. The cylinders and cylinder frame windows are stouter on the L-frames that give the L-frames a bit better margin of safety over the K-frames.

 

[JFrame]

In regard to frame size, here's another comparative pic to go with the fine photo Aarondgraham posted above...

On the upper step is a 686 L-frame...

On the lower step, left to right, are a 360PD J-frame, a 60-Pro J-frame, and a 65 K-frame.

I don't have an N-frame -- unless you count the Governor, whose cylinder proportions sort of blow the frame comparisons to heck...

All the guns in the photo are chambered in .357...

 

[WestTexShooter]

Ruger
GP - General Purpose. 100 a good starting point? IDK. 3”, 4”, 6”, etc. easy

SP - Special Purpose. 101follows 100? “ designations. Again easy.